<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    div{
        border:1px solid red;
    }
    #div2{
      margin:100px;
      padding:100px;
    }
    #div3{
      width: 500px;
      height:500px;
    }
  </style>
  <title>Document</title>
</head>
<body>
  <div id="div1">
    <div id="div2" >
      <div id="div3"></div>
    </div>
  </div>
</body>
</html>